Hen walking funny/ de calcified leg bones

I have a 3 1/2 year old Barred Rock. She has always been a bit on the heavy side. A couple months ago she began walking funny. It's hard to explain. She takes little mincing steps, almost stepping on her feet. It seems uncomfortable for her, like it hurts a bit.

I took her to the vet and he ran several tests. The only thing he could find was it seemed like the bones of her upper legs were not as solid as they should be. They looked kind of like they were de calcified. He had no idea what is wrong. She is eating fine and wants to be with everyone but definitely can't walk very good or jump up very good. I just want to know if anyone out there has any idea what my poor Bruiser Girl has and if they have any ideas on how to make her feel better.

Just wondering does she lay eggs anymore? Hens who are older can have reproductive problems such as internal laying or egg peritonitis. They sometimes exhibit problems walking, lameness, or may walk like a penguin. I don't know if those hens have problems with decalcification of bones or not. Does she eat layer feed or have access to crushed oyster shell or egg shells fed back to her?

She has a commercial layer feed and they have oyster shell mixed in and in cups around the area. I also give them yogurt. She only lays eggs once in a while. For a time last year she layer eggs without any shells at all. This year they had shells. The doctor said her abdomen is empty of any mass. It's not really a penguin walk, it's kind of an old lady shuffle.